Split corona shield for ground switch entry



April 4, 1967 J. A. TURGEON 3,312,796

SPLIT CORONA SHIELD FOR GROUND SWITCH ENTRY Filed June 11, 1965 2 Sheets-Sheet 1 /flw Ji- 5; .Z j 34 1 14 Q if 45. INVENTOR. JOJ5W/4 rwwm/v M7444 5/10 5455?, 62291 {far/2w April 4, 1967 J. A. TURGEON 3,312,796

SPLIT CORONA SHIELD FOR GROUND SWITCH ENTRY Filed June 11, 1965 2 Sheets-Sheet 2 NVENTOR.

United States Patent 3,312,796 SPLIT CORONA SHIELD FOR GRO SWITCH ENTRY Joseph A. Turgeon, Toronto, Gntario, Canada, assignmto I-T-E Circuit Breaker (Canada) Limited, Port Credit.

Ontario, (Ianada, a limited-liability company Filed June 11, 1965, Ser. No. 463,223

6 Claims. (Cl. 200-48) This invention relates to a disconnect switch for extra high voltage systems having a grounding switch associated therewith, and more particularly is directed to a novel split corona shield which allows the grounding switch to engage its associated contact in a path of movement which is transverse to the path of movement of the disconnect blade of the switch.

In United States patent application Ser. No. 441,215 filed Mar. 19, 1965, in the name of Joseph A. Turgeon and assigned to the assignee of the instant invention, there is shown a switch assembly for use with extra high voltage systems (200-700 kv.; 1500-3000 amperes) which comprises the combination of a disconnect isolating switch and grounding switch. The disconnect switch is designed to operate subsequent to the interruption of load current and has an elongated contact blade which is rotatable about one end of the switch assembly in a single plane of motion between an open, and a closed position in engagement with a cooperating stationary contact jaw.

The ground switch includes an elongated blade which is pivotally mounted at the opposite end of the switch assembly, which blade moves between an open position, wherein it is stored in a plane which is parallel to the plane of motion of the disconnect blade, and a closed position wherein it engages its associated contact.

As more specifically described in the aforementioned application, the grounding switch is provided with operating mechanism which allows its elongated grounding blade to traverse a path of motion which provides maximum gap distance between the end of the grounding blade and any energized part of the switch assembly. Specifically such path of motion is a compound angular path which includes a horizontal movement of the grounding blade out of the plane of the disconnect switch and concludes in a path of movement which is transverse to the path of movement of the disconnect blade.

In accord with the aforementioned application, the instant invention is directed to extra high voltage disconnect switches, and specifically to a novel corona shield which makes possible the path of motion of the grounding blade thereof. Specifically, corona shields of the prior art generally take the form of an integral circular or similarly shaped ring constructed of material designed to prevent corona discharge. However, it may be readily appreciated that if the typical integral corona shield of the prior art were used in the disconnect switch of the Turgeon application, such shield would interfere with the final movement of the grounding blade, which is trasverse to the plane of the corona shield. Therefore, the instant invention provides a corona shield adjacent the cooperating disconnect and grounding jaws which has a portion thereof removed so that the grounding blade may pass therethrough and engage its jaw in a path of movement which is transverse to the plane of motion of the disconnect blade. Such corona shield makes it possible for the grounding blade to travel in a path of motion which provides maximum gap distance between its tip and energized parts of the system and also provides the necessary shielding function for preventing corona discharge.

Accordingly it is an object of the instant invention to provide a corona shield adjacent the stationary contacts of a disconnect and grounding switch system which allows the path of movement of the grounding blade to be transverse to the plane of motion of the disconnect switch.

Another object of the instant invention is to provide a novel corona discharge shield positioned adjacent the cooperating contact structure of associated disconnect and grounding switches, wherein said corona discharge shield has a portion thereof removed at the point at which the path of movement of the grounding blade intersects the corona discharge shield.

Other objects and a fuller understanding of the instant invention may be had by referring to the folio-wing description and claims in which:

FIGURE 1 is a front elevation view of the over-all switch assembly embodying the instant invention.

FIGURE la is a plane view of the switch assembly along the arrows 1a1a of FIGURE 1 showing the path of movement of its grounding switch.

FIGURE lb is an end view taken along the arrows 1b of the switch assembly of FIGURE 1 showing a different view of the path of movement of its grounding switch.

Referring initially to FIGURE 1, and with reference to the aforementioned application, a switch assembly 20 is shown which comprises the combination of a disconnect isolating switch generally shown as 30 and grounding switch generally shown as 50. The switch assembly extends upward from ground surface 22 by support structures 2'4, 26 respectively. Cross support member 28 is connected between the upper ends 25, 27 of the support structure 24, 26. Stationary insulator support stacks 32, 34 extend upwardly from the support structures 24, 26 respectively with there also being a rotating insulator support stack 36 extend-ing upward adjacent insulator support stack 32. Disconnect switch 30, which may be of the general type shown in United States Patent 2,673,902, entitled, Disconnect Switch, issued Mar. 30, 1954, to G. B. Heberlein, is designed to operate subsequent to the interruption of load current appearing in bus 38. Switch 30 includes an elongated contact blade 40 which is typically mounted at one end to a rotatable hinge support 42 at the upper end of insulator support stacks 3 2, 36. The opposite, or contact end, 44 of the disconnect switch blade 40 engages a gooperating stationary contact jaw 45 at the upper end of insulator stack 34, when in the closed position as shown in FIGURE 1. A detailed description of the apparatus for opening and closing the disconnect blade, which forms no part of the instant invention, may be had by referring to United States Patent 3,143,608, entitled, Operating Mechanism for Disconnect Switch, issued Aug. 4, 1964, to the inventor of the instant invention.

Cooperating grounding switch 50 includes an elongated blade 52 having a beaver-tailed contact blade 54 at one end and pivoted at its other end to the upper end 27 of support structure 26 as generally shown by the numeral 100. Beaver-tailed end 54 of the grounding blade 52 engages jaw contact 102 at the upper end of insulator stack 34 when the grounding blade is in its closed position.

As is well known in the art, increased isolation protection is provided subsequent to the opening of disconnect switch 30 by moving the elongated contact arm 52 of the grounding switch 50 into the dotted line position shown as5-2' such that it will be in engagement with its cooperating upper contact 102. Movement of the grounding switch contact blade 50 between its open position shown as 52 and its closed position shown as 52' is provided by turning crank wheel 56 which may be manually activated or driven by conventional motor drive 57 connected thereto.

As described in the aformentioned application, Ser. No. 441,215, it is desirable that the elongated blade 52 J of the grounding switch be stored in the same plane as the support structure 24, 26, the insulating stacks 32-36, and the disconnect switch 3%. However, when so stored in this position, movement of the blade directly into the closed position shown as 52' along a path confined to this plane will not provide the necessary minimum gap clearance between the tip 54 of blade 52 and energized parts (bus 38) during the entire travel of the blade 52. The Turgeon application solves this problem by providing unique blade operating means which provides movement of the blade horizontally out of the storage plane such that the combined movement is a predetermined path, shown dotted 'by 200 in FIGURES 1a, 1b, which maintains the desired minimum gap clearance. The exact definition of the path of movement may be found in the 'Turgeon application and such reference is incorporated herein. For the purposes of this invention, it is sufficient to note that as the grounding blade tip 54 approaches its jaw 102, its path of movement is transverse to the path of movement of the disconnect blade 40. The relative transverse displacements of the paths of movement of the grounding blade 52 and the disconnect blade 40 is indicated in FIGURE 1a by the right angle notation indicated at 201. It is to be understood however that the path of movement of the grounding switch blade is shown perpendicular for illustrative purposes only and that the actual angle between the two paths of movement is not critical and need not be 90.

Adjacent the contact jaws 45 and 102 are located two shields 58, 59 for preventing corona discharge. shield 58 (FIGURES 1a and 1b) is a conventional ringshaped structure similar to the corona discharge shields 60 shown above insulator stacks 32, 36. Corona shield 59 however, is shown as a split corona shield (see FIG- URE 1), that is, as having a portion thereof removed as at 61 to allow the grounding switch blade to pass therethrough and engage its associated jaw 102.

By providing a split corona shield, i.e. with a portion thereof removed, it is now possible to have the grounding blade 52 conclude its movement in a path which is transverse to the plane of movement of the disconnect switch, while at the same time still being able to provide a corona discharge shield, which shield is extremely desirable in such disconnect systems. 7

Although I have described my invention with a certain degree of patricularity, it is understood that the present disclosure has been made only by way of example and that numerous changes in the examples of construction and the combination arrangement of parts may be resorted to without departing from the sphere and scope of the invention as hereinafter claimed.

The embodiments of the invention in which an excluiive privilege or property is claimed are defined as folows:

1. A disconnect switch comprising:

first and second terminals, said first terminal being at a first potential; a

main blade means pivotally connected to said first terminal, said main blade means movable in a first plane of motion into and out of engagement with said second terminal;

second blade means pivotally connected to a point at a second potential and movable in a predetermined path of movement from an open position to a closed position engaging said second terminal, said path of movement being transverse to said first plane of motion as said second blade means approaches its closed position;

and shielding means positioned adjacent said second terminal, said shielding means being shaped to allow said second blade to engage said second terminal in a path of movement which is transverse to said plane of motion.

Corona 2. A disconnect switch comprising:

first and second terminals, said first terminal being at a first potential;

main blade means pivotally. connected to said first terminal, said main blade means movable in a first plane of motion into and out of engagement with said second terminal;

second blade means pivotally connected to a point at a second potential and movable in a predetermined path of movement from an open position to a closed position engaging said second terminal, said path of movement being transverse to said first plane of motion as said second blade means approaches its closed position;

and shielding means positioned adjacent said second terminal, said shielding means having a portion thereof removed at the point at which the path of movement of said second blade means intersects said shielding means.

3. A disconnect switch comprising:

first and second terminals, said first terminal being at a first potential;

main blade means pivotally connected to said first terminal, said main blade means movable in a first plane of motion into and out of engagement with said second terminal;

second blade means pivotally connected to a point at a second potential and movable in a predetermined path. of movement from an open position to a closed position engaging said second terminal, said path of movement being transverse to said first plane of motion as said second blade means approaches its closed position;

and shielding means positioned adjacent said second terminal in a plane parallel to said first plane of motion, said shielding means having a portion thereof removed at the point at which the path of movement of said second blade means intersects said shielding means.

4. The disconnect switch of claim 3 wherein said shielding means is a split corona ring.

5. In a disconnect switch having first and second terminals; main blade means pivotally connected to the first terminal and movable in a first plane of motion into and out of engagement with the second terminal; and grounding blade means pivotally connected to a point of ground potential and movable in a predetermined path of movement from an open position to a closed position engaging the second terminal, the path of movement of the grounding blade means being transverse to the first plane of motion of the main blade means as the grounding blade means approaches its closed position; the improvement comprising:

shield-ing means positioned adjacent said second terminal in a plane parallel to said first plane of motion, said shielding means having a portion thereof removed at the point at which the path of movement of said grounding blade means intersects said shielding means.

6. The device of claim 5 wherein said shielding means is a corona ring having a portion thereof removed at the point at which the path of movement of said grounding means intersects the plane of said corona ring.

References Cited by the Applicant UNITED STATES PATENTS 2,154,665 4/1939 Christensen 20048 3,024,328 3/1962 Burdeshaw 20048 X 3,036,184 5/1962 Sabol et al 200-49 X ROBERT K. SCHAEFER, Primary Examiner.

H. HOI-IAUSER, Assistant Examiner. 

1. A DISCONNECT SWITCH COMPRISING: FIRST AND SECOND TERMINALS, SAID FIRST TERMINAL BEING AT A FIRST POTENTIAL; MAIN BLADE MEANS PIVOTALLY CONNECTED TO SAID FIRST TERMINAL, SAID MAIN BLADE MEANS MOVABLE IN A FIRST PLANE OF MOTION INTO AND OUT OF ENGAGEMENT WITH SAID SECOND TERMINAL; SECOND BLADE MEANS PIVOTALLY CONNECTED TO A POINT AT A SECOND POTENTIAL AND MOVABLE IN A PREDETERMINED PATH OF MOVEMENT FROM AN OPEN POSITION TO A CLOSED POSITION ENGAGING SAID SECOND TERMINAL, SAID PATH OF MOVEMENT BEING TRANSVERSE TO SAID FIRST PLANE OF MOTION AS SAID SECOND BLADE MEANS APPROACHES ITS CLOSED POSITION; AND SHIELDING MEANS POSITIONED ADJACENT SAID SECOND TERMINAL, SAID SHIELDING MEANS BEING SHAPED TO ALLOW SAID SECOND BLADE TO ENGAGE SAID SECOND TERMINAL IN A PATH OF MOVEMENT WHICH IS TRANSVERSE TO SAID PLANE OF MOTION. 